Dashboard
A panel just below the windshield and stretching across the front of
the car, containing gauges, switches, and instruments for car
operation.

Deceleration
Negative acceleration; the rate of change in velocity as a car slows
down during braking.

DIN
Stand for Deutsche Industrie Normen or German industrial standards.
DIN horsepower, a German rating similar to SAE net horsepower is the
output of a fully equipped engine fitted with all the normal
accessories.

Displacement
The volume vacated by the piston of an engine as it moves downward in
its cylinder.

Differential
A gear system that transfers power from the driveshaft (or the
transmission in a front-wheel-drive car) to the driving axles. It
permits the outer driving wheel to turn faster than the inner when the
car goes around a corner, to prevent skidding and tire scuffing.

Distributor
A component of the ignition system containing the breaker points and
cam, centrifugal advance and vacuum-advance mechanisms and a shaft
usually driven be the camshaft. The high voltage generated by the coil
passes into the center terminal of the cap mounted on top of the
distributor housing. From there, it passes down the rotor, and as the
rotor turns it distributes the current to terminals connected by
high-tension wires to the sparkplugs.

Drag Coefficient
A dimensionless number used in calculating the aerodynamic drag acting
on a car. The drag coefficient is a function of such factors as the
shape of a car and airflow through the car for cooling or ventilation.

Drive Shaft
The long, hollow tube with universal joints at both ends that carries
power from the transmission to the differential.

Drivetrain
The power transmitting components in a car, including clutch and
gearbox (or automatic transmission) driveshaft, universal joints,
differential, and axle shafts.

Dealer Participation
This is the amount contributed by the dealer to reduce the final
purchase price in the lease contract. Dealer participation can take
the form of a rebate or simply a discount. The dealer participation is
reflected in the lease contract as a capitalized cost reduction.

Depreciation
The amount by which property loses its value. In automobile leasing,
depreciation is the difference between the new car cost and the value
of the car at the end of the lease.

Disposition Fee
This is a fee you pay at the end of the lease, to the lessor, that
covers the lessor's cost of getting the vehicle ready for sale after
you have returned the vehicle. It is often applied against any deposit
you made at lease inception.

Drive Line
Everything in the Drivetrain except the engine and the transmission.

DOHC
Acronym for double-overhead camshaft. Refers to an engine with two
overhead camshafts.

DOHC (Dual Over-Head Cam)
An engine with two camshafts located above the cylinders. One drives
the intake valves and the other operates the exhaust valve.